Intersil ISL85001EVAL1Z Application Note

®

Description

The ISL85001EVAL1Z REV A kit is intended for use by
individuals with requirements for Point-of-Load applications
sourcing from 4.5V to 25V. The ISL85001EVAL1Z evaluation
board is used to demonstrate the performance of the
ISL85001 standard buck regulator.
The ISL85001 is offered in a 4mmx3mm 12 Ld DFN package
with 1mm maximum height. The complete converter
2
occupies less than 0.425in

Features

• Standard Buck Controller with Integrated Switching Power
MOSFET
• Integrated Boot Diode
• Input Voltage Range
- Fixed 5V ±10%
- Variable 5.5V to 25V
• PWM Output Voltage Adjustable from 0.6V to 19V with
Continuous Output Current up to 1A
• Voltage Mode Control with Voltage Feed-Forward
• Fixed 500kHz Switching Frequency
• Externally Adjustable Soft-Start Time
• Output Undervoltage Protection
• Enable Inputs
• PGOOD Output
• Overcurrent Protection
• Thermal Overload Protection
• Internal 5V LDO regulator

Applications

• General Purpose
• WLAN Cards-PCMCIA, Cardbus32, MiniPCI
Cards-Compact Flash Cards
• Hand-Held Instruments
• LCD Panel
• Set-top Box
What's Inside
The Evaluation Board Kit contains the following materials:
• The ISL85001 EVAL REV A board
• The ISL85001 datasheet
• This EVAL KIT document
Application Note
area.
1
1-888-INTERSIL or 1-888-468-3774
Regulator Standard Buck PWM
December 1, 2008

Recommended Equipment

The Following Materials are Recommended to Perform
Testing:
• 0V to 25V Power Supply with at Least 5A Source Current
Capability, Battery, Notebook AC Adapter
• One Electronic Load Capable of Sinking Current up to 5A
• Digital Multimeters (DMMs)
• 100MHz Quad-Trace Oscilloscope
• Signal Generator

Quick Setup Guide

1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.
2. Connect the bias supply to VIN, the plus terminal to TP1
(VIN) and the negative return to TP2 (GND).
3. Verify that SW1 is on ENABLE.
4. Turn on the power supply.
5. Verify the PG is on and the output voltage is 2.5V for
VOUT(TP3).

Evaluating the Other Output Voltage

The ISL85001EVAL kit outputs are preset to 2.5V; however,
it can be programmed using resistor dividers using
Equation 1:
⋅
R 0.6V
1
----------------------------------
R =
2
V 0.6V
–
OUT
The output voltage programming resistor R
on the feedback resistor R
value of R is typically between 1kΩ and 10kΩ. If the output
1
voltage desired is 0.6V, then R
FIGURE 1. EXTERNAL RESISTOR DIVIDER
TABLE 1. SWITCH 1 SETTINGS
SW1 ENABLE
1 SW1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
|
Intersil (and design) is a registered trademark of Intersil Americas Inc.
All other trademarks mentioned are the property of their respective owners.
ISL85001EVAL1Z: 1A
will depend on
2
, as referred to in Figure 1. The
1
is left opened.
2
R1
EA
R2
0.6V
REFERENCE
OPERATING MODE
Enable or disable the buck controller
Copyright Intersil Americas Inc. 2008. All Rights Reserved
AN1443.0
(EQ. 1)
V
OUT